P517: PROSPECTIVE MULTICENTRIC STUDY ON INFECTIOUS COMPLICATIONS AND CLINICAL OUTCOME IN 230 UNFIT AML PATIENTS TREATED IN FIRST-LINE WITH HYPOMETHYLATING AGENTS ALONE OR IN COMBINATION WITH VENETOCLAX.
Authors: A. Candoni, M. Piccini, D. Lazzarotto, V. Bonuomo, M. Dargenio, M. Riva, L. Mellillo, C. Papayannidis, M. Stulle, G. Dragonetti, M. I. Del Principe, C. Cattaneo, C. Pasciolla, R. De Marchi, M. Delia, M. C. Tisi, M. E. Zannier, G. Nadali, M. Sciumè, A. Spadea, C. Sartor, D. Griguolo, E. Buzzatti, C. M. Basilico, C. Sarlo, A. L. Piccioni, R. Cairoli, A. Olivieri, L. Pagano
Journal: HemaSphere (2022)

Background: The hypomethylating agents (HMAs) are an important therapeutic option for older patients (pts) with AML and have become the backbone for combination regimens (eg, with Venetoclax). However, there are very limited real-life prospective studies regarding clinical outcome of these pts, including infectious complications and infection related mortality (IRM) during treatment. Aims: To investigate the infectious complications and clinical outcome in AML patients treated with HMAs± Venetoclax (V) outside of clinical trials. Methods: The recruitment of this prospective multicentric study (CE-Id-study:2908) has been completed on December 31, 2020. We enrolled 230 AML pts with a median age of 75 years (range 25-94); 157 pts (68%) had >2 relevant comorbidities. Of the 230 cases, 132 (57%) received a first-line therapy with a combination of HMAs+V while 98 (43%) were treated with HMAs monotherapy (azacitidine or decitabine). A total of 1550 cycles of HMAs have been administered (680/1550 with HMAs+V). Results: The best response achieved, with HMAs treatment, was: CR in 44% of cases (57,6% with HMAs+V and 25,5% with HMAs alone, P=0,0001), PR in 17% and SD in 14% of cases (ORR 61%; 72% in HMAS+V and 46% in HMAs alone, P=0,0007). The microbiological or radiological proven infectious complications (almost one) occurred in 160/230 (70%) of pts, mainly pneumonia (in 42% of pts) and/or bacteremia/sepsis (one or more events in 29% of pts). Febrile neutropenia (one or more episodes) occurred in 38% of pts and 14 cases of Covid-19 (6%) were reported. After a median follow-up of 9 months (1-24) from the start of HMAs therapy, 144 (63%) pts died and 86 (37%) were alive. The 1 yr OS probability was 46% with a median OS of 10,3 months (11 months in HMAs+V and 9 months in HMAs alone; P=ns). The primary causes of death were: progression of AML (42%), Infection (26%-37/144), Infection+AML (24%), other causes (8%). The IRM was 26% and 19/144 (13%) pts died of infectious complication while in CR/PR (16 in HMAs+V group and only 3 in HMAs group; P=0,005). Data on antibiotic prophylaxis, hospitalization, drug-doses modulation, are available and analyzed in this study. Summary/Conclusion: The results of this real-life, multicentric, prospective study, confirm a higher CR rate in pts treated with HMAs+V compared to HMAs alone (P=0,0001). However, we found a high rate of infectious complications and IRM (26%) with a higher infection related deaths in patients in CR/PR who were treated with HMAs+V (P=0,005). Findings from this study highlight the critical relevance of infection prevention in reducing infectious mortality, which adversely impacts the OS of this frail AML population.